1. Field of the Invention
The invention relates to a connector for a flat cable.
2. Description of the Related Art
A flat cable has a plurality of electric wires arranged parallel to one another. A connector is used to connect ends of the wires in the flat cable to other circuit components. One such connector is disclosed in Japanese Utility Model Application No. 1-132078 and also is shown in FIG. 54 herein. The connector of FIG. 54 includes a housing 1 with a groove 2 for receiving the flat cable. A holder 4 holds the terminal end of the flat cable in the groove 2 of the housing 1. More particularly, the flat cable includes a plurality of electric wires 5, each of which has a cover 5A and a core 5B. The covers 5A and cores 5B adjacent the end of the cable are sandwiched between the holder 4 and the housing 1 so that a front portion of the core 5B is exposed outwardly from the housing 1. The connector of FIG. 54 is used with a mating housing 6, as shown in FIG. 55. The mating housing 6 has terminal fittings 7 that elastically contact the front portions of the respective cores 5B. In this manner, the cores 5B and the mating terminal fittings 7 become electrically conductive with each other.
The above-described connector does not hold the front portion of the core 5B. Thus, the front portion of the core 5B can move up from the housing 1 and can be bent laterally. Accordingly, there is a possibility that the front portion of the core wire 5B will contact the terminal fitting 7 with insufficient pressure when the housing 1 and the mating housing 7 are connected. As a result, a reliable continuity connection cannot be obtained.
There is also the possibility that the resin of the housing 1 or the holder 4 may deform during cooling of the molded resin, after the resin is cooled or due to heat generated after the holder is mounted on the housing. Such deformation of the resin could cause a gap between the housing 1 and the holder 4. Accordingly, there is a fear that the small diameter cores 5B may move apart from the holding groove 2 and may penetrate into the gap between the housing 1 and the holder 4. Thus, adjacent cores 5B could contact each other.
Japanese Patent Application Laid-Open No.2000-77123 discloses a shielded connector for a flat cable. The shielded connector includes a plug-side connector mounted on the flat cable and a receptacle-side housing fixed to a circuit substrate. The plug-side connector has a housing, a plurality of terminal fittings fixed in the housing, and a shield mounted on and covering the housing. The flat cable has a plurality of shielded electric wires that have a shielding layer and a core. The core of each shielded electric wire of the flat cable is soldered to a terminal fitting, and the shielding layer of each shielded electric wire is connected to the shielded shell. The receptacle-side connector has a housing with terminal fittings and a ground. The plug-side connector fits on the receptacle-side connector to connect the terminal fittings of both connectors. The shielding shell and the ground also become conductive to each other.
The above-described conventional shielded connector has many component parts. It is possible to reduce the number of parts by bringing the cores and the receptacle-side terminal fittings into contact without the plug-side terminal fitting. However, the cores are flexible, and it is difficult to insert and position the flexible cores in the housing. Thus, mounting efficiency is low.
The cores could be disposed along the outer surface of the housing. However, the shielding shell interferes with the receptacle-side terminal fittings and the cores when they contact each other. Therefore, a notch must be formed on a region of the shielding shell that corresponds to the cores disposed on the outer surface of the housing. However, the notch does not display a shielding function and there is a fear that noise is generated.
Additionally the terminal fittings of the above-described shielded connector has the terminal fittings arranged parallel with one another on the front face of the receptacle-side housing, and shielding members are formed on the right and left surfaces of the receptacle side housing. Only the shielding members function for connecting the shielding shell and the circuit substrate to each other. Thus the shielding member has a small region corresponding to the plug-side housing. The number of portions for connecting the shielding members and the plug-side shielding shell to each other is small. Therefore there may be insufficient shielding.
The present invention has been made in view of the above-described situations. Accordingly, one object of the invention is to provide a connector capable of holding a front end of a core of a flat cable. Another object of the invention is to provide a connector that prevents movement of the cores of the wires of a flat cable. An additional object of the invention is to provide a connector for a flat cable that prevents adjacent cores from contacting each other. A further object of the invention is to provide efficient shielding for a connector for a flat cable.
The invention is directed to a connector with a housing made of synthetic resin. The connector is used with a flat cable that has a plurality of electric wires. Each wire has a conductive core and an insulation cover. The insulation cover is removed at the terminal end of each wire to expose the core.
The housing has an outer surface with cover disposing portion for receiving portions of the insulation covers of the wires near the exposed cores. The housing further comprises core holding means for holding the exposed cores so that the cores cannot move. The core holding means may comprise core holding grooves that are arranged parallel with one another on the outer surface of the housing. A depth of each core holding groove with respect to the outer surface of the housing may be larger than an outer diameter of each of the cores, and the cores may be disposed individually along rear the core holding grooves. Mating terminals can be inserted into the core holding grooves for connection to the individual cores.
A wiring path for the insulation covers of the wires held on the outer surface of the housing preferably is perpendicular with a wiring path for the cores held individually by the core holding means.
A core holder preferably is mounted on the housing so that front portions of the cores are sandwiched between the housing and the core holder. Thus it is possible to prevent the core from moving or curving. The core holder preferably is mounted on the housing for movement between a temporary locking position, where the cores can be inserted between the core holder and the housing, and a main locking position, where the cores are retained between the core holder and the housing. An assembling operation can be performed easily by delivering the housing to a flat cable-mounting site with the core holder in the temporary locking position. The core holder then is moved to the main locking position to retain the cores to the housing. As a result, the contact pressure between the mating terminal fitting and the cores is secure, and a reliable continuity connection is obtained.
Each electric wire may be shielded and may have a shielding layer formed on the outer periphery of the cover. The covers are held on the cover-disposing portion of the housing by a short-circuiting member fixed to the flat cable in a way to short-circuit the shielding layers of the shielded electric wires to each other and by a fixing means for fixing the short-circuiting member to the housing.
The short-circuiting member for short-circuiting the shielding layer of each of the electric wires may be fixed to the flat cable, and the cover holding means may comprise a locking piece that is integral with the housing and can be locked to the short-circuiting member. Because the cover holding means is integral with the housing, the cover of the shielded electric wire can be held without using a separate member. Therefore the number of component parts can be reduced.
Each core is inserted into the rear end of the core holding groove. As noted above, each core holding groove is wider than the outer diameter of the core. Thus even if the plug-side housing deforms, the core will not slip out of the core holding groove and remains accommodated therein. In other words, adjacent cores can be held reliably separately on the outer surface of the housing. Further, the shielded electric wire of the flat cable is disposed along the outer surface of the housing. Therefore the shielded electric wire can be positioned more easily than a construction in which it is inserted into an opening formed on the housing.
The electric wire of the subject connector preferably is disposed in an L-shape along the outer surface of the housing. Hence, it is possible to prevent the electric wire from slipping out of place in the axial direction of the wire.
According to the above-described construction, the core holding means holds the core in a movement-prevented state in the core holding groove. Thus the core can be connected reliably to the mating terminal that has been inserted into the core holding groove.
The short-circuiting member of the above-described connector serves the dual function of short-circuiting the shielding layers to each other and holding the covers of the electric wires on the cover-holding portion. Therefore fewer components parts are used in the present invention than in the case where the cover-holding means is separate from the short-circuiting member.
The invention also is directed to a shielded connector comprising a plug-side connector connected to a flat cable and a receptacle-side connector on a circuit substrate. The plug-side connector is constructed such that the core of each shielded electric wire of the flat cable is disposed along an outer surface of a plug-side housing. A plug-side shielding shell then is mounted on the plug-side housing and shielded layers of the shielded electric wire are connected to each other. The shielding shell can hold the core holder. Therefore, the shielding shell and core holder can be mounted on the housing at a time and at a site where the shielding shell and core holder are mounted on the housing. Therefore it is easy to perform the assembling work.
The receptacle-side connector has a receptacle-side housing fixed to the circuit substrate. The receptacle-side housing has receptacle-side terminal fittings connected to the circuit substrate and a ground that also is connected to the circuit substrate. The plug-side connector can be fit on the receptacle-side connector to connect the core to the receptacle-side terminal fitting, and to connect the plug-side shielding shell to the ground.
The receptacle-side connector has a receptacle-side shielding shell that corresponds to a core holding region on the outer surface of the plug-side housing. The receptacle-side shielding shell is connected to the plug-side shielding shell when the connectors are fitted on each other.
The receptacle-side shielding shell and the ground preferably are integral with each other.
The receptacle-side shielding shell may have right and left side walls and a rear wall that correspond to right and left side walls and a rear wall of the plug-side housing respectively. The receptacle-side shielding shell may further have a connection portion connected to the plug-side shielding shell and formed on each of the right and left side walls and the rear wall thereof.
According to the above-described construction, the receptacle-side shielding shell corresponds to the rear surface of the plug-side housing as well as the right and left side surfaces thereof. Thus improved shielding effect can be obtained. The portions of connection between the receptacle-side shielding shell and the plug-side shielding shell are formed not only on the right and left side surfaces thereof but also on the rear surface. Thus a large number of connection portions are formed on the receptacle-side shielding shell and the plug-side shielding shell. Hence, improvement of the shielding effect can be achieved.
The receptacle-side housing preferably has a tubular fit-on portion that can accommodate the plug-side housing. The receptacle-side terminal fitting is disposed inside the tubular fit-on portion, and the receptacle-side shielding shell is disposed outside the tubular fit-on portion.
The receptacle-side shielding shell may have an inwardly projecting slip-off prevention locking piece. The receptacle-side housing may have an erroneous fit-on prevention projection that projects in from an inner surface of the fit-on tubular portion and a locking space formed therein. The receptacle-side shielding shell is placed in a slip-off prevention state by accommodating the locking piece in the locking space and by engaging the locking piece with an inner wall of the locking space. The receptacle-side shielding shell has the slip-off prevention slip-off prevention locking piece projecting inward from the rear wall thereof. Thus it is possible to prevent the receptacle-side housing from becoming large. Additionally, the erroneous fit-on preventing projection prevents the plug-side housing from fitting on the receptacle-side housing with the plug-side housing disposed in an improper direction.
The plug-side shielding shell preferably has an elastic contact spaced from the outer surface of the plug-side housing on which the cores are disposed. The elastic contact engages the outer surface of the receptacle-side shielding shell elastically, when the receptacle-side connector and the plug-side connector are fitted on each other.
The receptacle-side shielding shell of the above-described shielding connector is conductive to the plug-side shielding shell and confronts the core disposing region of the outer surface of the plug-side housing when the connectors have been fit on each other. Thus the receptacle-side shielding shell and the plug-side shielding shell surround the cores and the receptacle-side terminal fitting to display a high shielding function.
The ground and the receptacle-side shielding shell of the above-described shielding connector are integral with each other. Thus, fewer components parts are used, as compared to the case where the ground and the receptacle-side shielding shell are separate.
The plug-side housing of the above-described shielding connector and the cores on the outer surface of the plug-side housing are accommodated in the tubular fit-on portion of the receptacle-side housing. Thus the cores are not exposed. Further, the wall of the tubular fit-on portion partitions the receptacle-side shielding shell from both the receptacle-side terminal fitting and the cores. Thus, there is no fear that the receptacle-side shielding shell contacts the receptacle-side terminal fitting or the cores.
The receptacle-side shielding shell of the above described shielding connector is sandwiched elastically between the elastic contact portion of the plug-side shielding shell and the tubular fit-on portion. Therefore, the plug-side shielding shell and the receptacle-side shielding shell can be connected reliably to each other at a predetermined contact pressure. Further, the elastic contact is spaced from the outer surface of the plug-side housing on which the cores are disposed. Hence, there is no fear that the elastic contact portion interferes with the cores.